/**
 * Copyright (c) 2012-2016, www.tinygroup.org (luo_guo@icloud.com).
 *
 *  Licensed under the GPL, Version 3.0 (the "License");
 *  you may not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *
 *       http://www.gnu.org/licenses/gpl.html
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 */
package org.tinygroup.tinytest.contextloader;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.springframework.beans.factory.support.BeanDefinitionReader;
import org.springframework.beans.factory.support.DefaultListableBeanFactory;
import org.springframework.context.ConfigurableApplicationContext;
import org.springframework.context.annotation.AnnotationConfigUtils;
import org.springframework.context.support.GenericApplicationContext;
import org.springframework.test.context.support.AbstractContextLoader;
import org.springframework.util.StringUtils;
import org.tinygroup.commons.tools.ArrayUtil;

public abstract class AbstractGenericContextLoader extends AbstractContextLoader {

    protected static final Log logger = LogFactory.getLog(AbstractGenericContextLoader.class);


    /**
     * Loads a Spring ApplicationContext from the supplied <code>locations</code>.
     * <p>Implementation details:
     * <ul>
     * <li>Creates a standard {@link GenericApplicationContext} instance.</li>
     * <li>Populates it from the specified config locations through a
     * {@link #createBeanDefinitionReader(GenericApplicationContext) BeanDefinitionReader}.</li>
     * <li>Calls {@link #customizeBeanFactory(DefaultListableBeanFactory)} to
     * allow for customizing the context's DefaultListableBeanFactory.</li>
     * <li>Delegates to {@link AnnotationConfigUtils} for
     * {@link AnnotationConfigUtils#registerAnnotationConfigProcessors(org.springframework.beans.factory.support.BeanDefinitionRegistry) registering}
     * annotation configuration processors.</li>
     * <li>Calls {@link #customizeContext(GenericApplicationContext)} to allow
     * for customizing the context before it is refreshed.</li>
     * <li>{@link ConfigurableApplicationContext#refresh() Refreshes} the
     * context and registers a JVM shutdown hook for it.</li>
     * </ul>
     * <p>Subclasses must provide an appropriate implementation of
     * {@link #createBeanDefinitionReader(GenericApplicationContext)}.
     *
     * @return a new application context
     * @see org.springframework.test.context.ContextLoader#loadContext
     * @see GenericApplicationContext
     * @see #customizeBeanFactory(DefaultListableBeanFactory)
     * @see #createBeanDefinitionReader(GenericApplicationContext)
     * @see BeanDefinitionReader
     */
    public final ConfigurableApplicationContext loadContext(String... locations) throws Exception {
        if (logger.isDebugEnabled()) {
            logger.debug("Loading ApplicationContext for locations [" +
                    StringUtils.arrayToCommaDelimitedString(locations) + "].");
        }
        GenericApplicationContext context = new GenericApplicationContext();
        prepareContext(context);
        customizeBeanFactory(context.getDefaultListableBeanFactory());
        if (!ArrayUtil.isEmptyArray(locations)) {
            createBeanDefinitionReader(context).loadBeanDefinitions(locations);
        }
        AnnotationConfigUtils.registerAnnotationConfigProcessors(context);
        customizeContext(context);
        context.refresh();
        context.registerShutdownHook();
        postRefresh(context);
        return context;
    }

    protected void postRefresh(GenericApplicationContext context) {

    }

    /**
     * Prepare the {@link GenericApplicationContext} created by this ContextLoader.
     * Called <i>before</> bean definitions are read.
     * <p>The default implementation is empty. Can be overridden in subclasses to
     * customize GenericApplicationContext's standard settings.
     *
     * @param context the context for which the BeanDefinitionReader should be created
     * @see #loadContext
     * @see org.springframework.context.support.GenericApplicationContext#setResourceLoader
     * @see org.springframework.context.support.GenericApplicationContext#setId
     */
    protected void prepareContext(GenericApplicationContext context) {
    }

    /**
     * Customize the internal bean factory of the ApplicationContext created by
     * this ContextLoader.
     * <p>The default implementation is empty but can be overridden in subclasses
     * to customize DefaultListableBeanFactory's standard settings.
     *
     * @param beanFactory the bean factory created by this ContextLoader
     * @see #loadContext
     * @see org.springframework.beans.factory.support.DefaultListableBeanFactory#setAllowBeanDefinitionOverriding(boolean)
     * @see org.springframework.beans.factory.support.DefaultListableBeanFactory#setAllowEagerClassLoading(boolean)
     * @see org.springframework.beans.factory.support.DefaultListableBeanFactory#setAllowCircularReferences(boolean)
     * @see org.springframework.beans.factory.support.DefaultListableBeanFactory#setAllowRawInjectionDespiteWrapping(boolean)
     */
    protected void customizeBeanFactory(DefaultListableBeanFactory beanFactory) {
    }

    /**
     * Factory method for creating new {@link BeanDefinitionReader}s for
     * loading bean definitions into the supplied
     * {@link GenericApplicationContext context}.
     *
     * @param context the context for which the BeanDefinitionReader should be created
     * @return a BeanDefinitionReader for the supplied context
     * @see #loadContext
     * @see BeanDefinitionReader
     */
    protected abstract BeanDefinitionReader createBeanDefinitionReader(GenericApplicationContext context);

    /**
     * Customize the {@link GenericApplicationContext} created by this ContextLoader
     * <i>after</i> bean definitions have been loaded into the context but
     * before the context is refreshed.
     * <p>The default implementation is empty but can be overridden in subclasses
     * to customize the application context.
     *
     * @param context the newly created application context
     * @see #loadContext(String...)
     */
    protected void customizeContext(GenericApplicationContext context) {
    }

}